The sum of two numbers is 28 and their product is seven. Find the sum of the reciprocals of the numbers.
This one has me confused. How can their product equal 7 if 7 is prime?
1+27 027 14+14 196
2+26 052 13+15 195
3+25 075
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The sum of two numbers is 28 and their product is seven. Find the sum of the reciprocals of the numbers.
This one has me confused. How can their product equal 7 if 7 is prime?
1+27 027 14+14 196
2+26 052 13+15 195
3+25 075
This is just a very basic algebra problem.
x+y=28
xy=7
(1/x)+(1/y)=?
Hello, ceasar!
There is a marvelously sneaky trick for this one . . .Quote:
The sum of two numbers is 28 and their product is seven.
Find the sum of the reciprocals of the numbers.
This one has me confused.
How can their product equal 7 if 7 is prime?
WHO said these are whole numbers ??
We have: .x + y .= .28 . [1]
. . . . . . . . .xy . = . .7 . .[2]
Divide [1] by [2]: . x + y . . .28
. . . . . . . . . . . . . ------- .= .---
. . . . . . . . . . . . . . .xy . . . . 7
. . . . . . . . . . . x . . .y
And we have: .--- + --- .= .4
. . . . . . . . . . .xy . . xy
- - - . . . . . .1 . . 1
Therefore: - -- + -- .= .4 . . . . ta-DAA!
- - - . . . . . .y . . x
